:Calcium – zinc stabilizers

.Metal soaps are a type of heat stabilizers for PVC that are composed of a mixture of at least two metals, with one metal responsible for color preservation in the initial processing stages and the other metal responsible for long-term heat stability, such as calcium-zinc (Zn) stabilizers, which have been widely used in PVC applications for over 25 years. These materials are generally based on metal carboxylates and sometimes incorporate other elements such as aluminum or magnesium to enhance their performance when combined. In some PVC applications that require high heat stability, organic materials such as soybean oil epoxies or antioxidants can be used as co-stabilizers or auxiliary stabilizers to reinforce the heat stability of the material

.Due to its properties such as high transparency, good mechanical and electrical properties, and environmental compatibility, this heat stabilizer can be widely used in many flexible and rigid PVC applications

.This calcium-zinc stabilizer is a potential technical substitute for most other stabilizer systems, including lead and barium-zinc. Calcium-zinc stabilizers are more expensive than other metal soap stabilizers mainly due to the specialized stabilizers required to meet the specific needs of these applications. One important reason for replacing lead stabilizers with this stabilizer is that it is non-toxic and has been approved for use in contact with food according to the European Union’s food contact regulations

:Calcium-zinc heat stabilizers are used in the industry in three forms

powdered calcium-zinc:

. powdered calcium-zinc stabilizers, which are widely used as non-toxic and sanitary stabilizers, and are commonly used in food packaging, medical equipment, wires and cables, flooring, pipes and fittings, profiles, synthetic leather, and more. The thermal stability of powdered calcium-zinc stabilizers is not as good as lead salts and they have a specific oily property with poor transparency. In order to improve thermal stability and transparency, some additives are usually incorporated to enhance performance, including phenols, polyols, phosphates, beta-diketones, and other antioxidants

Liquid calcium-zinc:

.Liquid calcium-zinc stabilizers have an oily appearance and are light yellow in color. Generally, liquid calcium-zinc stabilizers have lower thermal stability compared to powdered stabilizers, but they have better transparency. These stabilizers require the addition of organic phosphates, antioxidants, and auxiliary stabilizers for optimal performance. Various solvents such as hydrocarbons and plasticizers are added to adjust viscosity. Liquid stabilizers are used in PVC products where the amount of plasticizer used is higher, typically above 10-20 phr (parts per hundred resin). In fact, the use of these stabilizers is common in soft and semi-rigid PVC applications. Liquid metal-mixed stabilizers are a suitable replacement for cadmium stabilizers in these applications. These stabilizers are formulated to achieve specific conditions such as proper initial color, long-term stability, good transparency, resistance to oxidation and degradation, and compatibility with all types of PVC, fillers, and pigments

Calcium-zinc paste:

.Calcium-zinc paste stabilizer is suitable for hygienic and odorless products that do not require transparency, and it is also approved for health. It is commonly used in medical accessories and hospital supplies such as oxygen masks, droppers, blood bags, medical injection equipment, as well as refrigerator gaskets, gloves, toys, hoses, and more. This stabilizer can be used as an alternative to Tin-based stabilizers in transparent food packaging or as a substitute for Tin carboxylates in PVC films. It is suitable for extrusion and injection applications, and adding epoxy-based soybean oil can enhance its properties